Heater core sloshing sound.

On my 03 Taco whenever I open the heater temperature control valve I almost immediately hear sloshing sounds coming from the heater core area. And it is quite loud. There is no coolant smell or loss and heater works perfectly. It's been doing this for some time now. Is there anyway to "burp" the heater core? I'm assuming trapped air (or a partially open temperature control water valve).

 

Sounds like coolant is a little low. Try parking your truck on an incline, let it cool off, remove radiator cap, crank it, let it warm up and when you stop seeing bubbles top it off and put the cap back on.

 

i had to put a Tee right at the heater valve to bleed out the air out of the coolant.

 

If you take the coolant line loose there it's the top of the system to fill when you leave the cap on. It's risky about breaking the heater core if it's never been taken off before though.